The invention relates to a method for operating a charging device of an energy store of a motor vehicle, wherein during multi-phase charging with the charging device, a rectifier device is used for each phase for generating a charging voltage for the energy store, whereas during single-phase charging by the charging device only one rectifier device is active. In addition, the invention relates to a charging device for an energy store of a motor vehicle, which has a control device and for each connecting cable associated with a phase a rectifier device for generating a charging voltage for the energy store, wherein a first connecting cable that is connected to a first rectifier device can be used during single-phase charging.
Recently, motor vehicles with an electric energy store providing larger amount of energy have been proposed, wherein the energy of the energy store can be, for example, at least partially converted into driving energy for the motor vehicle, as is known for hybrid and electric vehicles. To be able to charge such electric energy store of a motor vehicle, charging devices are known, whose main task is to convert the electric power provided on at least one connecting cable into a suitable charging voltage for charging the energy store which is a DC voltage. Charging devices have been also known that can be used for multi-phase electrical power, for example a two-phase or three-phase charging. Typically a connecting cable and a rectifier device are associated with every phase.
It is desirable that charging devices suitable for multi-phase charging should also be suitable for single-phase operation, so that users of motor vehicles can recharge the energy store also on a single-phase infrastructure, i.e. can therefore use single-phase electric power. Known prior art charging devices are constructed to use a first connecting cable connected to a first rectifier for single-phase charging. If an applied voltage is detected at the first connecting cable, for example with a suitable voltage measuring device, while no voltage is detected at to the other second connecting cables for the other phases, only the first rectifier device connected to the first connecting cable is operated to perform the charging process.
Because a charging device is designed for a certain service life, the prior art charging devices require for the rectifier devices an increased service life, which results in higher costs for the charging device.
It should also be noted at this point that the term rectifier device does not restrict the device to perform only a rectifier function, but describes modules for the different phases, which in addition to a rectifier may also include other electrical components, for example, filters, especially power factor correction filters and the like. Moreover, a rectifier device as a module may also include a total of several rectifier stages.